Effect on planarian motility by 51 μM γ-nonalactone, 200 μM cocaine or by 200 μM cocaine + 51 μM γ-nonalactone, as indicated. The bars were generated from the average of 12 worms each. The error bars represent the standard error of the mean. The γ-nonalactone by itself did not affect planarian motility compared to control worms (p > 0.05, two-tailed t-test). On the other hand, cocaine significantly decreased planarian motility compared to control worms (p < 0.001, two-tailed t-test). The presence of the γ-nonalactone decreased the apparent potency of cocaine to decrease planarian motility (p < 0.001, two-tailed t-test).